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SVMorningStar · 24-08-2011, 18:50

I plan to be hauling my boat in Oct. for a bottom job. After an issue with a leaky stuffing box (coinciding with the bilge pumps going south- fun, fun!), I am considering pulling the shaft and changing over to a dripless seal while I have it out of the water. I was wondering what downsides there might be to this kind of system. Any input or comparisons?

Chief Engineer · 24-08-2011, 19:09

I am not a fan of PSS seals.

Standard stuffing box with Gore packing is all I use.

cwyckham · 24-08-2011, 19:11

Love mine. Have to remember to "burp" it after putting boat back in water to get water in to cool it.

If you have a configuration such as mine where a failed coupling will allow the shaft to push into the boat due to the thrust on the propeller, then the boat will start to fill with water when the spring on the dripless gland runs out of trouble. Ask me how I know.

Solved by putting the engine into reverse or using a large hammer to get the shaft back into position.

neilpride · 24-08-2011, 19:20

I have for 6 years now a dripless stufing box made from tides marine , the model is strong lip seal or something like that, all of this years never a isue, not a drip, if the lip seal fail, i have a replacement seal just in the shaft between the coupling and the stufing box , just break the old one , and fit the new one , this is stuff is very simple , in case the seal fail is going to be drips and not a complete disaster, i love it....

stillbuilding · 25-08-2011, 02:53

Quote:

Originally Posted by Chief Engineer

I am not a fan of PSS seals.

Standard stuffing box with Gore packing is all I use.

Why dont you like them Chief? I have heard of one which was torn off when the engine left its footings.

**Wotname** · 25-08-2011, 02:58

Both have downsides but I prefer the PSS seals to the stuffing box and I am willing to accept the downside for the advantages whereas I am not so inclined to do so with the stuffing box.

stillbuilding · 25-08-2011, 03:17

Quote:

Originally Posted by Wotname

Both have downsides but I prefer the PSS seals to the stuffing box and I am willing to accept the downside for the advantages whereas I am not so inclined to do so with the stuffing box.

Well, I have had both on various yachts and generally the PSS gave me less bother and was more suitable for yachts with shallow bilges for obvious reasons. This time I am giving both a pass and moving up to a Pegasus shaft seal which is more expensive than both of them put together but suits my ideal of a dry boat AND something more secure. Wartsilla make some less expensive varieties too.

yachtvalhalla · 25-08-2011, 04:06

Quote:

Originally Posted by SVMorningStar

I plan to be hauling my boat in Oct. for a bottom job. After an issue with a leaky stuffing box (coinciding with the bilge pumps going south- fun, fun!), I am considering pulling the shaft and changing over to a dripless seal while I have it out of the water. I was wondering what downsides there might be to this kind of system. Any input or comparisons?

I've used dripless seals for over 20 years without any problems except .... and this is a rare exception. When I installed a Seahawk Autostream feathering prop the hub of the prop came within a half inch of the water (cutlass) bearing. After a long layup in a marina we got underway and had to use the engine to get to an anchorage in front of a storm and darkness. I had a loud screeching noise develop and on investigation found the water in the PSS was boiling! No lubricating water was getting through the water bearing, the cause of which I discovered the next day after sailing into a less than desirable anchorage, anchoring and riding out 2 meter seas through the night. The cause was marine growth between the prop hub and inside the water bearing which was blocking the ingress of the lubricating water. That PSS has now been replaced with one for a power boat which has a nipple into which I run water from the drain petcock on the heat exchanger. This positive flow lubricates the bearing nicely and the problem has gone away.

I even have an old one installed on the top of the rudder shaft at its entry to the boat ... replacing a stuffing box there that froze to the rudder shaft, broke the hose and nearly filled the boat when sailing downwind in large following seas.

Terry

SVMorningStar · 25-08-2011, 04:48

So what I think I'm hearing from those of you who have one is that they're great unless they decide to fail. That's kind of the case for any system. I'm just wondering what the likelihood of failure is.

Are they more likely to have issues than a stuffing box or less? Which could take more "abuse?" I"m just trying to figure out the pros and cons of each.

sdowney717 · 25-08-2011, 04:59

use a standard box with the GFO packing
the stuff is black silky smooth and does what it says.
Anyway other high tech seal methods are more work and worry like the comment about it boiling

http://www.gfopacking.com/

Quote:

GFO® fiber dripless packing is a braided propeller and rudder shaft packing that you can install and forget about. After 15 years of successfully handling demanding industrial pump applications, it's now proving itself in the marine field, too. It's already being used by the US Navy and Coast Guard and many commercial work and fishing fleets. And, it's approved by the American Bureau of Shipping.

article on how much maintenance the other shaft seals require
http://www.mysailing.com.au/news/the...ss-shaft-seals

so do you really want to pack it and forget it or do more work?

the other seals also tend to mist corrosive salt water
the gfo wont do that.

Steve W · 25-08-2011, 05:34

I don't know much about the PSS-style shaft seals, but can the bellows fail (tears, rips, dry rots or whatever) allowing a large water ingress? Is it thick like the traditional stuffing box multi-ply hose?

sdowney717 · 25-08-2011, 05:43

sure it can, inspect every few months and replace bellows every 6 years along with new seals.
rubber disintegrates, develops fine cracks, everything wears out given enough time due to planned obsolescence.
The idea for mandatory replacement is you dont want your boat sinking and they want to keep selling parts.

The rubber hose that connects many packing glands also requires replacement every so often. I bet there are a lot of boats with 20 year old hoses in them and it is not leaking yet.

**Don L** · 25-08-2011, 07:20

The only time I give any worry about my shaft seal is ........... when I read these threads.

**zeehag** · 25-08-2011, 07:31

my ericson has for the past 6 yrs been done with a traditional stuffing box with teflon packing, dripless kind. is awesome. no problem. dry boat.
my formosa has a flanged system no one bothered to properly install--i am trying to add gore tex stuffing to it....still pending. has taken over 3 months to slowly stuff it inside because no one packed it before install.
i sailed a boat for a year with failing pss..actually the shaft tube was failing not the pss.....is a good simplish system as long as all is working well and shaft is lubed with water. if not---- fixing them suxx and is very very wet. must check the hose clamps and bellows frequently.....